On the water heater, do you hear it clicking, can you see the spark? Do you have propane flowing to the propane valve on the heater (you will have to take the copper line loose at this valve to verify propane is flowing - obviously turn the propane off when doing this and have it on only to verify flow). If you have the spark igniter working and you have propane flow to the valve, then the valve is bad. Mine died last winter and it has been in constant use all winter. Fortunately they are easy to change.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof